Lk 12:49-53
[Jesus said to his disciples,] 49“I have come to set the earth on fire, and how I wish it were already blazing! 50There is a baptism with which I must be baptized, and how great is my anguish until it is accomplished! 51Do you think that I have come to establish peace on the earth? No, I tell you, but rather division. 52From now on a household of five will be divided, three against two and two against three; 53a father will be divided against his son and a son against his father, a mother against her daughter and a daughter against her mother, a mother-in-law against her daughter-in-law and a daughter-in-law against her mother-in-law.”
SET THE EARTH ON FIRE: Culturally, what Jesus probably meant by “earth” was not earth as habitation but “earth-oven.” Animal dungs were dried and used as fuel and were salted so that they would burn better. Jesus suggests that he came to light the oven, that is, to be a catalyst. But as used by Luke, the image is that of the earth’s inhabitants set “on fire” by the message of the Gospel.
Fire is used in Scriptures to symbolize God’s judgment where the just are purified and the evil ones destroyed (Mal 3:2-5). As metal is refined of dross by fire, so people are tested as genuine by life’s ordeals. Here, Jesus states that the purpose of his coming is to test the hearts of men and women, to separate the good from the evil.
Christ becomes a “sign of contradiction,” that is, people are divided over him—whether they are for him or against him. He cannot be ignored; one cannot remain neutral; one must take a stand. Since the world has values contrary to Christ’s, division results between those who accept Christ and those who reject him. His good news is bad news for those who refuse him.